What is new in Visual Studio 2010 and the .Net Framework 4.0

jQuery - In 2010 major changes has been done for high performance and standard javascript standards compliant JavaScript IntelliSense engine. Microsoft and Jquery group working together to make developer life easy, so Visual Studio 2010 will be the first version of Visual Studio to ship JQuery as a native part of the ASP.NET solution

MVC - All features of "Preview release of ASP.NET MVC" included in Visual Studio 2010
2010 make very easy to build Model-View-Controller aka MVC sites.
n Visual Studio 2010 we deliver the next generation of ASP.NET web tools that make it easy for developers to use TDD to build Model-View-Controller (MVC) based web sites. Wizard based interface to creating views, generating test project for MVC solution. Various templates are given.

ASP.NET MVC and Web Forms

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JQuery and XML

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HandleUnknownAction in ASP.NET MVC – Be Careful

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Summary of interfaces in 3.5 .NET framework IEnumerable, IQueryable and IList

IEnumerable - supports being used in a foreach statement and that's about it.
IQueryable - supports further filtering, paging, etc. Does not support random access via an indexer. Implements IEnumerable
IList - supports random access via an indexer. does not support further filtering. Implements IEnumerable